[ [  1,-1,-2, 2, 0,-1, 1, 0 ],
  [  0, 0, 1,-1,-2, 0, 0, 0 ],
  [  0, 0, 0, 0, 4, 1,-1, 0 ],
  [ -1, 0, 0, 0, 0, 0, 0, 0 ],
  [  0, 1, 0, 0, 0, 0, 0, 1 ],
  [  0, 0, 0, 0, 0, 0, 0,-1 ] ]